As he was inaugurated for his second term, President Obama urged the American people to seize the day and work with him to create a more caring, more constructive and safer country.

But his message was as much an exhortation to himself as to the nation. When he first entered the White House in 2008 it was on a wave of emotion and excitement. Everything seemed possible to the first black president, with his great oratory and his ability to enthuse everyone around him.

But the checks and balances of American politics, especially after the Republican victories in 2010, meant he spent his first term in political dogfights. The global recession and the continuing wars in Iraq and Afghanistan also blunted his impact.

But now he seems reinvigorated, ready for the fight and wanting the ordinary people to back him. He needs to succeed with his social initiatives like medicare and social security reforms - measures which could change the way Americans live and soften the devil-take-the-hindmost mentality which leaves so many people so terribly impoverished in the richest country in the world.

However his toughest battle will to be change America's gun laws. He knows that he is up against well-financed and politically-powerful lobbies, but is up for the fight. He sees it as a test of character and this as a perfect moment to begin the battle, with the horrors of the Sandy Hook schoolchildren slaughter still fresh in the nation's mind. If President Obama can introduce sensible gun controls, it will be an important victory for him.

No one denies that events conspired to an extent against him in his first term, but even he seems optimistic about what can be achieved over the next four years. It remains to be seen if ordinary Americans are fed up with the political elite and their private battles in Washington and are now ready for a radical change across a broad political spectrum. If President Obama can convince them of the value of his policies he may yet leave his mark on history.